On balance, probably not. The WHO reckons "vaccination of the elderly against flu reduces the risk of serious complications or death by 70-85%". But a new report from the Health Protection Agency suggests that, despite Britain's £150m programme to vaccinate 15 million-plus people (including three-quarters of the over-65s) each winter, having the jab makes no difference to an elderly person's chances of ending up in hospital with a more serious flu-related respiratory illness.

A US study last month also claimed there is "insufficient evidence" to determine the extent to which flu jabs cut the death toll in winter, if they do so at all, and that most reports on the flu vaccine had "greatly exaggerated its benefits". Part of the problem is that most research has involved fairly fit under-70s, whereas 75% of flu deaths are among over-70s. For these people, the vaccine may be just 23% effective.

So is it worth it? Most doctors seem to feel that while additional measures - such as treating chest infections and discouraging smoking - may be needed to help reduce flu-related hospital admissions among the oldest and frailest, the vaccine will still benefit most people by ensuring their eventual illness is less severe.

Dr Jeremy Harker, one of the authors of the latest study, says the jab has "demonstrable benefits" in alleviating the consequences of post-flu infections in the elderly. And Dr George Kassianos of the Royal College of General Practitioners says immunisation should be extended to the over-50s and young children so as to create "a more effective herd immunity". Yet another study, he notes, shows that over a 10-year period in the US the jab was associated with a 27% reduction in hospital admissions for pneumonia and a 48% reduction in deaths among older people. So don't write it off just yet.